Electron paramagnetic resonance study of Pr4+ ions doped in BaSnO3, Ba2SnO4, and Ba3Sn2O7

摘要

The isotropic electron paramagnetic resonance (EPR) spectra of powders with Pr4+ doped in the cubic perovskite BaSnO3 and the layered perovskites Ba2SnO4 and Ba3Sn2O7 were measured at 4,2 K. Very large hyperfine interactions with the Pr-141 nucleus were observed in all of the host materials, The results were analyzed based on the weak-field approximation, and the g values and hyperfine coupling constants A were obtained. The measured g values are much smaller than -10/7, showing that the crystal field effect on the behavior of a 4f electron is large. The value of g decreases from 0.646 (Pr4+/Ba2SnO4) to 0.606 (Pr4+/Ba3Sn2O7) to 0.583 (Pr4+/BaSnO3), which is caused by the increase of the crystal field due to the shortening of the Pr4+-O2- distance, On the other hand, the hyperfine coupling constants are almost constant: A = 0.060 cm(-1). (C) 1998 Academic Press. [References: 9]